1. Field of the Invention
The present invention relates to an apparatus for decomposing perfluorocarbons and harmful gas using a high-density confined plasma source, and more particularly, to an apparatus for decomposing perfluorocarbons (PFCs) and harmful gas using a high-density confined plasma source that is to decompose and eliminate perfluorocarbons (PFCs) used as a processing gas for dry etching of insulators in semiconductor fabrication processes.
2. Background of the Related Art
Generally, perfluorocarbons (PFCs), known as one of greenhouse gases that contribute to global warming, are used as a processing gas for dry etching of insulators in semiconductor fabrication processes.
Perfluorocarbons (PFCs) consumed incompletely and emitted in the atmosphere from the chamber after completion of the semiconductor fabrication processes are subjected to environmental regulations and thus required to decompose prior to their release to the atmosphere. For this purpose, a variety of scrubbers are used.
Korean Patent No. 10-0808979 discloses a patented technique for “processing fluorocarbon sources”.
The prior art describes a technique that includes: generating an electrical arc between at least one negative electrode and at least one positive electrode in a high temperature region; generating thermal plasma having a tail-shaped flame burning upward with the electrical arc and a plasma gas in the high temperature region; forming a reactive thermal mixture from a solid particle fluorocarbon source including at least one fluorocarbon under the tail-shaped flame of the thermal plasma to dissociate the fluorocarbon compound into at least one fluorocarbon precursor or reactive species; and cooling down the reactive thermal mixture to form at least one desired fluorocarbon compound from the fluorocarbon precursor or reactive species.
Out of the prior art, a burn & wet type scrubber using heat and liquids is widely used in the fields of semiconductor, but it is likely to generate NOx gases at high temperature for decomposition of perfluorocarbons, where the release of NOx is also banned. Reducing the temperature to prevent this problem adversely ends up with unsatisfactory efficiency of the perfluorocarbon decomposition.
Further, a scrubber using another plasma involves in consuming high electric powder to achieve high decomposition efficiency or, when installed in an exhaust pipe, causes erosion of the exhaust pipe or damage on the pump.
When using a plasma, the straight line arrangement of exhaust pipes 150′ and 151′ connected to the top and bottom portions of reactors 150, as illustrated in FIG. 1, causes the plasma to diffuse up and down, accordingly leading to erosion of the exhaust pipe 150′ and damage on the pump. This also decreases the density of plasma to reduce the decomposition efficiency.